Set screw and the like



Jan. 20, 1925 1,523,932

v A. W. DAVIES SET SCREW AND THE LIKE Filed June 18, 192:5 I

Patented Jan. 20, 1925 UNITED STATES PATENT OFFICE.

ALBERT VIILLIAM DAVIES, F GLASGOW, SCOTLAND, ASSIGNOR TO MAVOR & COULSON, LIMITED, OF GLASGOW, SCOTLAND.

SET SCREW AND THE LIKE.

Application filed June 18,

To all 20 72cm it may concern Be it known that I, ALBERT WILLIAM Davncs, a subject of the King of Great Britain and Ireland, and residing at Mile- End, Glasgow, Scotland, have invented new and useful Improvements in or Connected with Set Screws and the like, of which the following is specification.

This invention refers to set screws and the 0 like, hereinafter referred to as set screws, for use generally and particularly suitable for use under conditions where vibration, or heating (or both) occurs. F or example, for securing cutter picks in the blocks of cutter chains of coal cutting machines, and generally in substitution for the usual cupped and hardened set screw, and the invention relates to improvements in or con nected with the known type of set screw which at its outer end is provided with a pad to engage with the surface on which the screw is to be tightened, the pad being mounted in a socket formed in the outer end of the set screw from which socket the pad projects and is capable of rotation about the axis of the screw, so that when the pad is in bearing contact it does not rotate with the screw in the process of tightening.

According to this invention the pad comprises a body principally of spherical form,

a seating 0t non-spherical form at its base,

say, a flat surface portion of non-spherical form, a contact portion at its head comprising, for example, a cutting or indenting edge, say of circular form, or other form of edge or edges the depth of the socket in the outer end of the set screw and the size oi the pad being such that the sides oi? the socket extend above the centre of the spherical body of the pad and are closed in to retain the pad in position, and the form of seating and socket being such as will restrict rotational movement of the pad to rotation only about the axis of the set c5 screw.

In one method of construction a hardened steel ball may be used on which a seating of non-spherical form is formed by grinding to produce, say, a flat base and opposite the base a contact portion may be produced by grinding so as to present, say, a circuiar cutting or indenting edge. For use in conjunction with this type of pad the set screw may be formed with a cylindrical socket at its end, the axis of; the socket being co-axial 1923. Serial No. 646,071.

with the screw, the inner end of the socket presenting aplane transverse surface, and the depth of the socket and size of the pad is such that the sides of the socket project above the original centre of the ball. The pad is placed in the socket so that its fiat base rests upon the surface of the inner end of the socket and the metal at the sides is then closed in to embrace the body of the pad in such a manner that the pad is free to rotate about the axis of the set screw, but is prevented from rotating other wise or of moving endwise to any appreciable extent.

An example of a set screw according to this invention is illustrated in the accompanying drawing, the view being an elevation partly in section.

In the construction illustrated A designates a cylindrical socket formed in the end of the screw, and B the pad which is formed with a flat base 2 and at its head with a concave recess, the axis of which lies in the axis of the screw, producing a circular cutting or indenting edge 3. A ter the pad has been placed in position the lips of the socket A are closed in, the pad being thereby retained in position and while free to rotate only about the axis of the set screw is prevented from moving endwise to any appreciable extent.

It will be recognized that itis not essential for the seating to be a plane fiat surface, for example, it may be concave or formed to present an annular bearing surface. Further, the contact portion may, for example, comprise straight edges, say, parallel or intersecting.

I claim 1. A set screw having a socket at its outer end, a pad mounted in the socket, the pad comprising a body principally of spherical form, a seating of non-spherical form at its base, a contact portion of non-spherical form at its head, the depth of socket and size of pad being such that the socket extends above the centre of the spherical body of the pad, and the sides of the socket closed in to retain the pad in position, for the purposes set forth.

2. A set screw having a socket at its outer end, a pad mounted in the socket, the pad comprising a body principally of spherical form, a seating of non-spherical form at its base and a contact portion of non-spherical form at its head formed from a hardened steel ball, the depth of socket and size of pad being such that the socket extends above the centre of the spherical body of thepad, andthe sides'of the socket closed in'to retain the pad in position, for the'purposes set forth. I r

3. A set screw having acylindrical socket at its outer end, the axis of 'the socket be-. ing co-axial with the screw, a pad mounted in the socket, the pad comprising 'a body principally of spherical fornna flat surface seating atits base,'acontact portion of'nonspherical form at its head, 't-hedepth "of socket and the size ot the pa d being such that the socket extentls'above the centre of the spherical body'of-the padpand the lips of the-"socket closed in to retain the pad in position, for thepurposes-set forth.

4; I A-set screw having a cylindrical: socket atits outer end, the axis of the socket'being oo-a-xial With-the screw, a pad'inounted in thesocket, the pad comprising "a body principally of spherical fOL ll'l, a fiat surface seating at its base, an edge contact portion at its head, the depth of socket and size of pad being such that the socket extends above the centre of the spherical body of the pad. and the lips of'the socket closed in to retain the pad in position, for the purposes set forth.

5. A set screw having a cylindrical socket at its outer end, the axis of the socket being co-axial Withthe screw, a pad mounted in the'socket, the pad comprising a bod principally of spherical form, a seating of nonspherioal form at its base and a contact portion at its head fornied from a hardened-steel ball, thedepth of socket and size of pad beingsuch that-the socket: extends above the centre of the spherical body ofthe-pad, and the lips of the socket closed into i'etaintlie pad'in position, for thepnrposes-set forth.

ALBERT WlLIJIAh I DAVIES. 

